That's very strange, especially considering that I can quote Wikipedia with no problems:

Research looking at swearing in 1986, 1997, and 2006 in America found the same top ten words were used of a set of over 70 different swear words. The most used swear words were fuck, shit, hell, damn, goddamn, ass, bitch, and sucks—these ten made up roughly 80% of all profanities. Two words, fuck and shit, accounted for one third to one half of them. The phrase "Oh my god" accounts for 24% of women's swearing.

So I'm not sure what they are filtering, but I'm pretty sure it's not profanity.